The proposed study will examine longitudinal changes in youth's cultural orientations/experiences and psychosocial and physical well being in a rapidly growing segment of the U.S. population: Mexican American youth from predominantly immigrant families. Latinos are the largest and fastest-growing ethnic minority group in the nation, and Mexican origin individuals comprise 67% of this population. Building on our cross- sectional study of Mexican American families with adolescent siblings (R01-HD39666), we propose to collect two additional points of measurement from four family members (i.e., mothers, fathers, target adolescents, and older siblings) in the 246 families who participated in the original project. Our proposed study will span 8 years in the lives of Mexican origin youth (ages 12 to 21 for target adolescents and 15 to 24 for older siblings) and their parents. Our focus on how unfolding cultural and family socialization processes are linked to well being in late adolescence and emerging adulthood promises to make significant contributions to the field of human development which has paid almost no attention to normative developmental processes among ethnic minority youth and families (Garcia Coll et al., 1996;McLoyd, 1998). The specific aims of our study are as follows: (1) to chart the longitudinal course of the multiple dimensions of youth's cultural orientations and experiences and the interrelations between these dimensions from early adolescence through emerging adulthood and to identify the moderators of change patterns;(2) to describe the longitudinal linkages between youth's cultural orientations and experiences and those of their parents and siblings and to identify the moderators of those linkages;and (3) to examine the longitudinal linkages between youth's developing cultural orientations/experiences and their psychosocial and physical well being. Home interviews and time-use data (via seven phone interviews) will be collected from four family members. Hierarchical linear modeling will be used to address our specific aims. Public Health Statement: The proposed project will provide important insights about the ways in which youth's cultural orientations and experiences are linked to their positive development (e.g., school achievement, family relationship qualities) and psychological and physical well being (e.g., risky behaviors, depressive symptoms) overtime and to the conditions under which youth's cultural values and experiences promote or hinder their well being.